Biosensor-based estimation of kinetic and equilibrium constants

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Updated: Sep 21, 2026

Bio-layer Interferometry for Measuring Kinetics of Protein-protein Interactions and Allosteric Ligand Effects
13:57

Bio-layer Interferometry for Measuring Kinetics of Protein-protein Interactions and Allosteric Ligand Effects

Published on: February 18, 2014

J G Quinn1, R O'Kennedy

  • 1School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland.

Analytical Biochemistry
|February 22, 2001
PubMed

The steady-state affinity constant for the interaction of glutathione S-transferase (GST) with anti-GST immunoglobulin (IgG) was determined by solution-phase equilibrium analysis. A Biacore concentration assay for the determination of free anti-GST IgG was employed giving a Kd value of 6.83 x 10(-10) M. A simple 1:1 solution-phase, equilibrium model approximated the data well. Furthermore, saturation studies showed a maximum occupation of approximately 50%. The choice of affinity-capture ligand, used to anchor anti-GST IgG to the hydrogel, influenced the interaction curves, as evidenced by contact-time-dependent dissociation-phase curves. This was apparent when performing the analysis on anti-mouse Fc-coated surfaces. When the interaction was conducted on a protein A-coated CM5 sensor chip, the interaction conformed well to ideal behavior and was selected for kinetic analysis of the GST interaction.

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